Rivet setting mechanism



wm-a3 s sheets-Shen 1 @c 4, 1938@ L. Q HUCK RIVET SETTING MECHANISMoriginal Filed may 14, 1935 @at 4, 33 L, Q, HUCK RIvEjr SETTING mcmxmsorigami Filed may 14, 3535 3 Shams-Sheet `2 INVENTOR. olas Haci OCL 4,L.. C. HUCK RIVET SETTING MEcHANIsM original Filed Mayvm, 193s 5sheets-sheet 3 Patented Oct. 4, 1938 RIVET SETTING MECHANISM Louis C.Huck; Buchanan, Mich., assignor to Buxon Holding Corporation, acorporation of Michigan original application May 14, 1935', serial No.21,472. Divided and this application June 22,

1936, Serial No. 86,571

10 Claims.

The invention relates to a rivet setting mechanism and it has particularrelation to a mecha,- nism for setting rivets of a type including atubular element and a pin extending therethrough and which is insertedand set from one side of the structure to be riveted.

More particularly the invention constitutes an improvement in rivetsetting mechanisms over those disclosed in the copending applicationsfor patent of Louis C. Huck et al., Serial No. 615,544, filed June 2,1932, now Patent 2,053,718, granted Sept. 8, 1936, and Louis C. Huck etal., Serial No. 636,480, tiled October 6, 1932, now Patent 2,053,719,granted Sept. 8, 1936. This application l constitutes a division of mycopending application for patent, Serial No. 21,472, filed May 14, 1935.

. In the rst of the above mentioned copending applications for patent a.rivet setting mechanism was set forth which included a rivet setting gunand a iluid pressure boosting device connected thereto by ilexibletubing so that the gun might be used at points remote with respect tothe booster and without moving the booster each time the gun would bemoved. It also was set forth in this application for patent that airpressure would be used in the booster device for building up a liquiduid pressure which would be supplied to the gun for operating it duringthe rivet setting procedure. Moreover, this rivet setting mechanism wasso designed and constructed that by manipulating a trigger on the gun,operation of the booster device and setting of the rivet could becontrolled entirely by the operator manipulating the gun even though thebooster device would be located at some distance away.

In the above mentioned copending application vfor patent, Serial No.636,480, filed October 6, 1932, a rivet setting gun of somewhat diierentcharacter is disclosed which also operates in conjunction with a boosterdevice such as set forth in the iirst mentioned copending applicationfor patent. The gun in the second case includes two pistons one of whichoperates rst when the trigger on the gun is pulled to eiect a certainphase of the rivet setting operation and then upon completion of thisphase, the second piston automatically becomes operative to cause anauxiliary anvil to move over the head of the tubular part of the rivetto radially contract a portion thereof o into grooves in the pin forminga part of the rivet. Upon completion of this operation, the

liquid fluid pressure is automatically increased to such extent that therst piston continues its movement to break the pin at a predetermined 5Point.

satisfactory, certain improvements have been def sirable and form thebasis of this invention. These may generally be indicated in the objectsof the invention but a more detailed explanation wm be fourd in chedescription. objects of the invention additional to those outlinedhereafter will be apparent from this description, from the drawings towhich it relates and from the claims hereinafter set forth.

` One object of this invention is to provide a rivet setting gun whichis more eicient in operation and which may more easily be handled andmanipulated by the operator.

Another object of the invention is to provide an improved jaw mechanismand operating arrangement therefor which will enable using a smallerdiameter of barrel on the gun and also facilitate insertion of the jawsduring assembly of the gun. f

Another object of the invention is to provide an improved riveting gunor the like employing jaws therein, wherein means are provided formanually opening the jaws.

For a better understanding of the invention reference may be had to thedrawings wherein: l

Figure 1 is a longitudinal, cross-sectional view of a riveting mechanismconstructed according to one form of the invention;

Fig. 2 is an end view of the mechanism as seen from the left end ofFigure 1;

Fig. 3 is a cross-sectional view taken substantially along the line 3-3of Fig. 2;

Fig. 4 is a cross-sectional view taken substantially along the line 4--4of Fig. 3;'

Fig. 5 is a cross-sectional view taken substantially along the line 5-5of Fig. 4;

Fig. 6 is a cross-sectional view taken substantially along the line 6--6of Fig. 1;.

Fig. rI is a cross-sectional view takenv substantially along the line'l-l of Fig. 1;

Fig. 8 is a cross-sectional view taken substantially along the linefB-Bof Fig. 1;

Figj9 is a fragmentary cross-sectional view of a riveting mechanismconstructed according to another form of the invention;

Fig. 10 is a cross-sectional view taken substantially along the linellt-l0 of Fig. 9;

Fig. 11 is a cross-sectional view illustrating a rivet inserted inopenings in a structure to be riveted as seen prior to setting of therivet; and

Fig. 12 is a view similar to Fig. 11 illustrating the assembly after therivet has been set.

Since this application is a division of the copending case, Serial No.21,472, the means for supplying fluid under pressure to the rivetingmechanism herein disclosed has not been included. The riveting mechanismis connected to the iiuid pressure supply means solely by means of twoconduits and these have been included herein and are identified by thenumerals 24 and |23. These numerals correspond to the numeralsidentifying the same conduits in the parent case. Conduit 24 suppliesliquid which may be subjected to high pressure during the rivetl settingoperation. The conduit |23 4is an air supply line, which not onlysupplies air to the riveting mechanism, but which also provides a meansfor controlling the remote pressure developing means through operationof a trigger on the riveting mechanism.

vReferring now to Figs. 1 and 2, the riveting gun comprises a cylindercasting |10 having a thickenedupper portion |1| upon which a handle |12is detachably secured by means of bolts |13. It may be stated at thistime that the gun normally will be used with ythe handle uppermost andthe 4latter is so arranged with respect to the cylinder casting andother parts of the gun that a vertical line substantially through thecenter of gravity of the gun will pass upwardly substantially throughthe center of the handle so that the operator holding the gun suspendedfrom the handle will find the axis of the cylinder substantiallyhorizontal. This adds'to the ease with which the gun may be .manipulatedand operated. 'I'he casting |10 includes two bores |14 and |15 separatedby an integral wall |16, and a tubular piston rod |18. is journaled in abearing |19 provided in a central opening in the wall |16 forreciprocatory movement axially of the bores. The bearing terminates atits right end in a flange which abuts a shoulder |8| on the wall so asto prevent movement of the bearing towards the left, and at the right ofthe flange |80 a sealing ring |82 of cup-shaped character is provided soas to positively prevent fluid at the right side of the wall |16 fromowing along therod |18 to the left side thereof. A piston |84 is rigidlymounted on the rod |18 within the bore |14 and this piston has a sealingring |85 at its left side and around the rod to positively prevent nuidbetween the piston and the wall |16 from owing between the piston andpiston rod. 'I'he outer periphery of the piston is provided with sealingrings |86 similar to those mentioned which prevent uid from flowingbetween the cylinder wall and the piston periphery. At its right end,the piston rod projects through a closure head |81 held against ashoulder |88 by a ring |89 threaded into the end of the cylinder, andthe head |81 has a bearing |90 through which the rod projects. The innerend of this bearing is anged similarly to the bearing |19 and a sealingring is disposed in a recess in the head to prevent uid from flowingbetween the piston rod and the head.

In the bore |15 a similarpiston |94 is provided but this piston has aninner bearing associated therewith which may reciprocatev with thepiston on the piston rod |18. This bearing terminates at its right endln a ange |98 and a sealing ring |91 similar to those mentioned ismounted on the right end face of the piston for preventing fluid at theright side of the latter from owing between the piston rod and thebearing. The left side of the piston terminates in a tubular portion|98, which may reciprocate in a flanged bearing |9lsecured 'in anapertured head 200 that is held in the left end of the cylinder by athreaded sleeve 20|. A sealing ring such as mentioned may be provided atthe right side of the head 200 to prevent uid from escaping along thebearing.

At the left end of the tubular portion |98 of the piston |94, a. head203 is mounted for reciprocatory movement on the piston rod and abearing 204 may be provided between it and the rod,- and this head has atubular portion 205 slldable in bearing |99, and which abuts the portion|98 of the piston so that when the piston is moved to the left, the head203 moves therewith.

The head 203 at its left end terminates in three radially offset andaxially directed legs 206 spaced degrees apart as best shown by Fig. 6,and these legs are axially movable in recesses 201 formed in thecylinder head 200. Between the recesses inwardly directed legs 208arethereby formed on the head 200, as also shown by Fig. 6, and it maybe noted that the circumferential length of the recesses substantiallyis the same as the circumferential length of the legs 208. Referring nowboth to Figs. 1 and "l, axially beyond the end of the legs 208,-the head200 terminates in a cylindrical portion 209 of larger i diameter andthis tubular projection has Atwo rslots 2|0 spaced 60 degrees apart andwhich extend to the outer end thereof. An outer barrel sleeve 2|2 isreciprocable in the tubular portion 209 and the inner end of this sleeveat one point is provided with an outwardly directed projection 2|3adapted selectively to t in one of the openings 2|0. It will beappreciated that -the slot 2|0 will hold the barrel sleeve 2 I2 againstturning while permitting its reciprocatory movement and that bywithdrawing the barrel, it may be re-inserted with the projection 2|3disposed in the other slot 2|0 thereby positioning the barrel sleeve ina 60 degree displaced position. Reciprocatory movement of the sleeve 2|2is additionally guided and supported by a sleevel 2|4 (Fig. l1) threadedinto the end of the sleeve 20|, and it will be apparent that sleeve 2|4will normally prevent withdrawal of the bari'el sleeve 2|2 by abutmentwith the projection 2|3 on the latter. An inner sleeve 2li isreciprocatory in the sleeve 2|2 and the former, as best shown by Fig. 7,has three circumferentially spaced slots 2|6 of the same character asthe slot 201 shown by Fig. 6, and these slots receive radial projections2|1 at the inner end of the sleeve 2|2. From this description it will beappreciated that the two sleeves may reciprocate relative to one anotherand, with the parts arranged as shown by Fig. 1, the legs 206 on thehead 203 are in4 engagement with the projections 2|1 on the sleeve 2|2,while the endportions'of the sleeve 2|5 between the slots 2I6 are inengagement with the radial projections 208 on the head 200.

It will now be apparent that if piston |94 moves to the left, itwillmove the head 203 to the left and the engagement of the .legs 206 on the-latter with the projections 2|1 on sleeve 2|2 will cause the latter toVmove to the left. The sleevev2|5 may remain stationary and in abutmentwith the legs 208 on the cylinder head 208 as the legs 206 and 2|1 onthe head 203 and sleeve 2|2 may move axially in the slots 2|6 in thesleeve. reversed by removing the sleeve 2|4 and withdrawing the sleeves2|2 and 2| 5 and then reinserting them with the projection 2|3 on theouter sleeve dispod in the other of the slots This arrangement may be-tubular element 230.

2|0, and the reason for this selective arrangement is to enable settingyof different types of rivets as set forth in the previous applicationsfor patent mentioned.

The outer end of the piston rod |18 has an enlarged portionreciprocatory in the inner sleeve 2|5 and a reduced portion 22| threadedinto a tubular jaw operating member 222 that is also reciprocatory inthe sleeve 2|5. The member 222 at its outer end has a conical innerperiphery 223 terminating at the end of the member in a circularopening, and as best shown by Fig. 8, this conical surface has threeequally spaced grooves 224 of cylindrical character with the axis ofeach cylindrical surface substanti-ally parallel to the conical surface.These grooves respectively receive jaws 225 having outer cylindricalsurfaces seated in and movable along the grooves. From this it should beappreciated that the jaws m-ay be expanded or contracted by theirmovement along the grooves 224 while still obtaining full andcylindrical surface contact between the jaws and the grooves. It will benoted that the grooves are not greater than semi-circular in crosssection and this is advantageous in that it permits inserting the jawsthrough theinner end of the jaw operating member 222. If the jaws had tobe inserted through the front opening at the smaller end oi the conicalsurface 223, a larger diameter of the member 222 would be required andthis in turn would require larger diameters of the sleeves 2|2 and 2|5and hence the barrel of the gun would be larger land could not beinserted in certain places for riveting.

Each of the jaws has an axial extension at its inner end as indicated at221 that has a. slot 228 therein for receiving one of three radialprojections 229 on the outer end of a tubular sleeve 230, which extendsentirely through the piston rod in a reciprocatory manner and projectsfrom the right end thereof. This construction enables manually pullingthe jaws to the right relative to the operating member 222 by pullingthe outwardly projecting end of the tubular member 230 and this may beadvantageous after the riveting operation in the event the jaws areunduly wedged in the grooves 224. For normally urging the jaws towardthe left, a sleeve 23| is slidable on the sleeve 230 and is providedwith an annular shoulder 232 engaging the ends of the projections 221 onthe jaws. This sleeve is urged toward the left by a coil spring 233engaging the right end of the sleeve and which is disposed in a recess234 provided between the larger portion 220 of the piston rod and theBetween the ange 232 on the sleeve 23| and theend of the piston rodportion 22|, an annular ring 235 of rubber or the like is provided forcushioning the jaws when the rivet pin breaks and when the jaws tend toquickly move to the right with respect to the operating member 222 asthe result of recoil. It may be noted here that normally this will bethe action obtained so that the jaws will automatically' free themselvesfrom any wedging engagement with the grooves 224 as a result of recoilforce when the pin breaks, but in the event this does not occur or forany other reason it is desired to move the jaws to the right relative tothe member 222, the right end of the sleeve 230 may be gripped from theexterior of the gun and the sleeve pulled to move the jaws.

The inner surfaces of the jaws are generally cylindrical with the axisthereof substantially coinciding with the axis of the piston rod andsuch inner gripping surfaces are provided with grooves for gripping agrooved portion of the rivet pin. For engaging the tubular part of therivet, the outer end of the sleeve 2|5 terminates in an anvil 231 thathas a tubular projection 239, while the outer end of the sleeve 2|2terminates in anIanvil 239 having a slightly tapered entry opening 240.

The right and outer end of the sleeve 230 has a short sleeve 24| securedthereon, such as by pins or a split ring 242, and this short sleeve hasan enlarged bore at its left end containing a coiled spring 243 abuttingthe right endof the piston` rod |18. 'I'his arrangement insures movementof sleeve 230 with the piston rod |-18 when the latter moves to theright, so as to hold the lugs or ears 229 at the left end of the sleeveat the right end of the slots 228 in the jaws. In setting a rivet,breaking of the rivet pin causes the jaws to move to the right relativeto the piston rod |18, and hence relative to sleeve 230, and if the lugs229 were not at the right end of the slots 228 in the jaws, the jawsmight engage the lugs and break them ol. It may be added that the lengthof the slots 228 to the left of lugs 229 (as shown in Fig. 1) is greaterthan that permissible movement of the jaws relative to the piston rodand member 222 as governed by the linear space between the shoulder 232and the left end `of the piston rod portion 22|, so -that with the lugs229 normally maintained at the right end of the slots 228, engagement ofthe lugs with the left end of the slots-upon breaking of the pin`ordinarily will not occur.

The sleeve 24| enables manual pulling of the sleeve 230 so as to movethe jaws backwardly relative to the jaw openings 224. Thisisadvantageous if the jaws ever freeze in the openings, or if it isdesired to expand the jaws for any reason.

Now referring to Figs. 3 and 4, the casting |1| at the upper side of thegun, has an opening 244 in communication with the air line |23 and thispassageway in turn communicates with an opening 245 communicating with avalve passageway 246. The passageway 246 has a valve 241 thereinprovided with axially directed peripheral spaces 248 to allow air toflow therethrough, and the central portion of the valve is normallypressed against a valve seat 249 by means of a spring 250 engaging thevalve and an apertured bushing 25| threaded into the passageway 245. Thevalve seat 249 has a central opening to allow air to pass therethroughwhen the valve is unseated, and this opening communicates with anopening 252 communicating with the atmosphere. For unseating the valve241 a plunger 253 is reciprocable in a head 254 closing the left end ofthe passageway 246, and thisv plunger, as best shown by Fig. 1, isadapted to be moved by one end of a bell crank 255 pivoted on the handleas indicated at 256. The opposite end of the bell crank is engaged -by ashort arm 251 rigidly connected to a trigger 258 that .is pivoted asindicated at 259 on the handle. Thus, when the trigger is raised, theplunger 253 is moved toward the right unseating the valve 241 and thisin turn connects the conduit |23 to the atmosphere allowing airtoexhaust.

Referring to Figs'. 3, 4, and 5, the passage 244 is in communicationwith the right end of the bore |14 and the left end of bore |15 in thegun. 'I'his is effected by providing 4a longitudinal passageway 265, asshown by Fig. 5, extending through the casting |1| at one side of thecylinder bores, and which has its ends plugged and this passageway is incommunication with the bores` |14 and 15 by means of ports 266 and 261and by providing a second port 268, as shown by Figs. 4 and 5,communicating vwith the right end bore |14 and with the passage 244.Now, if the trigger is pulled, the conduitl |23 and the passage 244 areopened to atmosphere and the space at the right side of piston |84 andthe left side of piston |94 may exhaust to atmosphere. Conversely, whenthe trigger is released and the valve 241 closes, air under pressure mayow into tl space at such sides of the pistons |84 and i Referring alsoto Figs. 3 and 4, the liquid line 24 is threaded into a bushing 215disposed in a bore 216 in the casting |1|, and this bushing is heldagainst a seal 211 by a threaded bushing 218. l 'I'he bore 216 in turncommunicates with an aperture 219, communicating in turn with adownwardly directed valve bore 280 extending diagonally into the wall|16 and communicating with the bore |15 by a smallerv opening 28| andwith the bore |14 at the left end thereof,` as indicated'at 282. It maybe noted that the sides of the wall |16 and pistons |84 and |94 arerelieved so as to insure entry of liquid properly at the adjacent sidesof the pistons even though the latter are at the ends of their strokes.The lower end of the bore 280 has an apertured valve seat 283 adapted tobe closed by a ball v284 disposed in a sleeve 285 holding the 'seat inplace and having its upper end enlarged and threaded into the upper endof the bore 280. A spring 286 in the sleeve presses the ball against itsseat and the upper end of the spring is held by a cap 281 threaded onthe sleeve. At its lower end, the sleeve has one or more openings 288 sothat liquid flowing upwardly through the seat 283 may pass into the bore280 at the outside of the sleeve. Thus, liquid may flow upwardly fromthe bore |15 and through the valve, but it cannot fiow in the reversedirection, while liquid may flow either to or from bore |14 through thebore 280.

For introducing liquid under pressure to the bore |15 at the right sideof piston |94, a smaller opening 290 is formed in a tubular member 29|disposed in a bore 292 and this opening is in communication with theboreI 280 by means of an opening 293. The left end of the opening 290 isnormally closed by a small valve element 294 integral with a stem 295 oflarger diameter which may slide in the member 28|,and it will be notedthat around the valve element 294 the end face of the stem is of largerdiameter to provide a greater area for the oil to act upon once theelement is unseated from the end of opening 290. Thestem 295 is urgedtoward the right to hold the element 294 in valve closing position by astrong compressive spring 296 disposed in a. tubular cap 291 threadedinto the bore 292, and this spring abuts the left end of the cap at oneend and at its other end a flange 300 integral with a plunger 30| whichengages the stem 295. It will be seen that the'element 294 will not openuntil considerable pressure is applied and that once it opens, thelarger area against which the liquid may act at the end of the stem 295serves to hold the valve open even though the pressure should dropmaterially. The member 29| is held tightly in position by the cap 291engaging a collar 302 that in turn engages a bushing 303 abutting theleft end of such member 29|.

Suitable sealing rings 304 may be provided to prevent liquid fromseeping between the stem, bore, bushing 303 and member 29|.

When the valve stem is moved by liquid pressure, it moves past a port305 that communicates with an annular groove 3.06 lin the outer surfaceof member 29|, and the latter communicates with -an opening 301extending to the cylinder bore |15. For the purpose of preventingmovement of the stem by a pressure lower than that required to unseatthe valve element in the event any slight leakage occurs past the latterwhen it is in closed position, the peripheral surface of the end portionof the stem -is -provided with very minute grooves 308 which will allowany oil seeping past the valve element 294 to iioW directly into thecylinder. If some means of this character were notprovided it ispossible in the event of slight leakage past the valve element, that anoil pressure would be slowly built up against the end face of stemsuilcient to move it and open the valve before reaching a pressure thatalone would be suicient to unseat the valve element.

As best shown by Fig. 1, the system may be filled with oil by providinga tapered opening 3|0 in the casting |1| and tapered openings 3|| ateach side communicating respectively with the two bores |14 and |15.After filling the system, the opening 3|0 is closed by means of atapered plug 3|2 held tightly in place by means of a button 3|3 on aplate 3|4 that is secured by bolts 3 5 to the casting. For the purposeof facilitating removal of theplug 3|2, a screw 3|6 may be threadedthereinto and when screwed downwardly it may be engaged with the base ofthe opening 3|0 to dislodge the plug and force it upwardly.

Now referring to Figs. 11 and 12, the rivet may comprise a tubularelement 325 having an intermediate portion of smaller internal diameter,an external head 326 and a tubular portion projecting from the oppositeside of the structure to be riveted and which is indicated at 321. Therivet pin, which is indicated at 328, has a break neck 329 of smallerdiameter than the remainder of the pin, a series of locking grooves 330to the left of the break neck, a shoulder head 33|, a larger left endportionA 332, a head 333, and gripping grooves 334 at the opposite endof the pin. A spreader ring 335 is provided on the larger portion 332 ofthe pin and is adapted to increase in size whenthe head 333 engages itso as to provide a larger part for bulbing the tubular portion 321. ofthe tubular member.

When the rivet is set, the pin is pulled with the' reactionary forceapplied against the head 326, and this causes the head 33| rst to expandthe larger intermediate portion of the tubular member, then the head 333acting throughA the spreader ring 335 causes the tubular portion of thetubular member to bulb outwardly into a head as shown in Fig. 12, andthen the head 326 is contracted radially to force metal into the lockinggrooves 330 which are then disposed within the head, and then furthertension on the pin causes it to break at the break neck 329 then locatedat the outer side of the head 326. In setting the rivet, it is insertedas shown by Fig. 11 and the gunis moved into a position where the pinprojects into the jaws 221 and it will be recalled that the jaws havegrooves for receiving the grooves 334 on the pin. The operation of thesystem may now be described.

Assuming that the 'system is properly filled with oil and the air lineconnections are made, the gun is properly associated with the rivet pinand this brings the anvil portion 238 against the outer radial face ofthe rivet head 326. With the trigger 258 in closed position, air underpressure supplied through the conduit |23 is also supplied to the rightend of the bore |14 and the left end of the bore |15 and this maintainsthe pistons |84 and |94 adjacent the intermediate wall |16 of thecylinder casting, it being understood that the liquid in the bores atthe left side of piston |84 and at the right side of piston |94 isallowed to flow back through the conduit 24. When the trigger 258 ispulled, the line |23 is open to exhaust and this also opens the cylinderspaces in the gun at the right side of the piston |84 and at the leftside of the piston |94 to exhaust. As described in the parent case,opening the conduit |23 to exhaust by operatingmtkhetrigger 258 causesactuation of a booster thati'n turn forces liquid through the conduit 24and into the space at the left side of the piston |84. This causes thepiston |84 to move toward the right, carrying with it the piston rod |18and the jaw operating member 222. Positive and forceful contraction ofthe jaw members results lockingv them strongly to the rivet pin andcontinued movement ol the piston |84 will cause movement of the rivetvpin while the reactionary force is applied through the wall |16 andcasting |18 and cylinder head 20D, sleeve 2|5 and anvil 231 to the faceof the rivet head 326. The operations of expanding the tubular memberintermediate its ends and formation of the bulbed head from the tubularportion 321 of the rivet are then eiected in order, and, after formationof this bulbed head, very strong resistance is encountered to furthermovementl of the rivet pin and this causes the liquid pressure in thebarrel and in the liquid side to increase rapidly and when this pressurereaches a. predetermined amount `governed by the valve spring 296, shownin Fig. 4, the valve element 294 will be forced from its seat and thestem 295 will be movedto the left until liquid may llow into thecylinder bore |15 at the right side of piston |94. Then the piston |94begins to move to the left moving with it the outer barrel sleeve 2 I2and anvil 239 which forces the latter over the rivet head 326 and causesits radial contraction to force metal into grooves 330 of the pin. Uponcontraction of the head 326 of the rivet, resistance to movement ofeither of the pistons |84 and |94 will further increase, and this willcause the liquid pressure in the system to build up to a point where therivet pin will be so tensioned that it will break at the breakl neck329. Ordinarily, when the pin breaks, the recoil force on the jaws willcause the jaws to move rearwardly and the broken part to pass rearwardlythrough the jaws and through the piston rod and sleeve 230 and to beejected from the right end thereof.

If the trigger 258 on the. gun is now released, air pressure will againbe built up in conduit 23 as the valve 294 will be closed, and air underpressure will be built up at the right side of piston |84 and at theleft side of piston |94, causing these pistons to return totheiroriginal positions, thereby forcing the Vliquid at their oppositesides back through the conduit 24. As will be seen in Figure 4, theliquid at the right side of piston |94 may flow out of the cylinder bore|15 through the passageway 28| and past the ball 284 as the latter willbe unseated by the pressure on the liquid due to the air pressure at theopposite side of the piston,

Figs. 9 and 10 illustrate an improved form of Jaw arrangement in thegun. Here the jaws 225 engage at their inner ends a relatively heavy,

sleeve does not pass through to the other end of the piston rod |18.l'I'he spring 351 normally urges the inertia ring 354 and jaws forwardlyand with the jaws in the normally operative position shown a substantialspace 359 exists between the end of rod portion 22| and the ring.

'I'he jaws 225 are also and individually urged inwardly by springshaving intermediate coiled portions 360 disposed in slots 36| in themember 222 and each coiled portion is pivotal on a pin 362 projectingthrough the slot. Frontwardly, the coils have ends 363 extendingforwardly in recesses 364 in member 222, and which terminate in radialends 365 projecting through small openings 366 in such member and intoaxial grooves 361 in the jaws, respectively. The other ends of the coilshave radial ends `368 projecting into openings 369 in the jawsrespectively, and by pressing against the rear walls of such openings,such ends urge the jaws individually away from the outer end of member222.

When the rivet pin breaks, the large recoil force tends to throw thejaws back and relative to member 222, and it is important that the fullforce of this recoil not be absorbed by striking of the jaws against rodportion 22|. The spring 351 is occasionally not enough of a cushionagainst such force of the recoil. The ring 355, however, interposes aninertia force and its weight is such that the rearward throw of the jawsis slowed up owing to the fact that the jaws must pick up this weightand carry it with them, and while the jaws and ring both moverearwardly, the recoil force is dissipated enough that nal engagement ofring 355 with ,the end of rod portion 22| is not damaging to the jaws orring. 'Ihe spring ends 365 and 368 do not interfere with movement` ofthe jaws and the ends 365 particularly maintain the jaws against turningor circumferential displacement. 'Ihe ends 368, while normally urgingthe jaws rearwardly, are not strong enough to overcome spring 351 sothat the latter normally maintains the jaws seated in grooves 223 inmember 222. These ends 368 are provided to move the jaws rearwardly andexpand them when it is desired to withdraw an unset rivet gripped by thejaws, but manifestly it will be first' necessary to move sleeve 355rearwardly before the ends 368 can perform this function. To move sleeve355 rearwardly, an expanding tool 315 may be inserted from the right endof rod |18, and, while any suitable tool may be used, it is shown ascomprising a tube 316 having segments 311 separated by slots 318, and arod 319 threaded into the tube as indicated at 38|), and which has atapered head 38| for expanding the segments. When the segments areexpanded into gripping relation with sleeve 355 by turning rod 319relative to the tube 316, the tool may be pulled to the right so as tomove the sleeve.

Although more than one form of the invention has been illustrated anddescribed in detail, itA

of the casing, a barrel sleeve extending axially from one end of thecasing, a jaw enclosing and operating member in the sleeve and connectedto one end of the rod, jaws in the member, said jaws and member havingcooperating tapering surfaces, and means extending axially through thepiston rod and engaging the jaws for manually moving the latter, saidmeans extending beyond the opposite end of the rod for manualmanipulation.

2. A rivet setting mechanism comprising a casing, a tubular piston rodand piston reciprocable in the casing, a jaw actuating memberoperatively connected to the piston rod, jaws adapted to be contractedand moved by said member, means extending axially through the rod andengaging the jaws for manually moving the latter, and resilient meansfor holding said first means normally in abutting and engaging relationwith the Jaws.

3. A rivet setting mechanism comprising a casing, a tubular piston rodand piston reciprocable in the casing, a jaw actuating memberoperatively connected to the piston rod, jaws adapted to be contractedand moved by said member, means extending axially through the rod andhaving interlocking but play permitting engagement with the jaws vformanually moving the latter, and resilient means for normally preventingplay between the jaws and said first means.

4. A rrivet setting mechanism comprising a piston, a tubular piston rod,releasable gripping means operatively engaged by the rod at one endthereof, and means extending through the rod for releasing the grippingmeans.

5. In a riveting machine, a jaw actuating member, a plurality ofseparately movable jaws, means for urging the jaws into engagement withthe jaw actuating member,and other means normally urging the jaws out ofengagement with the member.

6. In a riveting machine, a jaw actuating member, a plurality ofseparately movable jaws, means for urging the jaws into engagement with.the jaw actuating member, and other means normally urging the jaws outof engagement with the member, the first means being more forceful thanthe second means.

7. In a riveting machine, gripping means for gripping and moving anelement, means movable relative to the gripping means for applyinggripping forces to the latter so as to grip and move the element, meanscarried by the second means and normally urging the gripping means intocooperative relation to said second means, and means also carried by thesecond means for urging the gripping means out of cooperative relationto the second means.

8. In a riveting' machine, a plurality of free jaws, a jaw actuating andcontracting member, means urging the jaws into operative positions, andindividual means for urging each jaw towards inoperative position.

9. In a riveting machine, a plurality of free jaws, a jaw actuating andcontracting member, means urging the l laws into operative positions,and individual means for urging each jaw towards inoperative position,said individual means comprising springs anchored on the actuatingmember and respectively engaging the jaws.

10. In a riveting machine, gripping means for gripping and pulling anelement, means for actuating and moving the gripping means, meansnormally urging the gripping means towards operative position, meansurging the gripping means to inoperative position, and an inertia memberseparate from but movable by the gripping means.

. LOUIS C. HUCK.

atl

